Effects of Astragalus polysaccharide on intestinal immunity and microbiota composition in SPF mice stimulated by lipopolysaccharide

MA Wanting; CUI Bo; HE Limei; CHEN Yanyan; DU Jiachao; BAI Xue

doi:10.13557/j.cnki.issn1002-2813.2025.22.018

Abstract：This experiment aimed to investigate the protective effects of Astragalus polysaccharide(APS)on lipopolysaccharide(LPS)-induced immune stress in mice.A total of 48 healthy male SPF mice aged four weeks and weighing 20 to 22 g were randomly divided into four groups with four replicates per group and three mice per replicate.From 1 to 21 days of the experiment,groups APS and APS+LPS were orally administered 100 mg/kg body weight(BW)APS,while the control group and group LPS received an equal volume of physiological saline.On day 22,groups LPS and APS+LPS were intraperitoneally injected with 100 mg/kg BW LPS to induce immune stress,whereas the control group and group APS were injected with an equal volume of saline.The pre-test period was seven days,and the formal test period was 22 days.The results showed that serum immunoglobulin G(IgG)content in groups APS+LPS and LPS was significantly higher than in the control group(P＜0.05),but the IgG content in the group APS+LPS was significantly lower than in the group LPS(P＜0.05).Serum levels of interleukin-1β(IL-1β),interleukin-6(IL-6),and tumor necrosis factor-α(TNF-α)in the group APS+LPS were significantly lower than those in the group LPS(P＜0.05).The TNF-α content in the group APS was significantly higher than in the control group(P＜0.05).Intestinal secretory immunoglobulin A(SIgA)content in the group LPS was significantly lower than in the control group(P＜0.05).The intestinal SIgA content in the APS+LPS group was significantly higher than that in the LPS group(P＜0.05),but significantly lower than in the control group(P＜0.05).The crypt depth in the group LPS was significantly greater than in the control group(P＜0.05),and the villus to crypt ratio was significantly lower than in the control group(P＜0.05).The villus height of the group APS+LPS was significantly higher than in the group LPS(P＜0.05),and the crypt depth was significantly higher than in the control group(P＜0.05),while the villus to crypt ratio was significantly lower than in the control group(P＜0.05).The villus height and crypt depth in group APS were significantly higher than in the control group(P＜0.05).The indexes of Chao1,Ace,Shannon,and Simpson,as well as the Sobs and the number of operational taxonomic units(OTUs)in the group LPS,were significantly lower than those in the control group(P＜0.05).Group APS+LPS had significantly higher levels of these indexes than the group LPS(P＜0.05),and showed no significant difference from the control group(P＞0.05).The study shows that APS can effectively alleviate LPS-induced intestinal morphological damage and microbiota dysbiosis in mice,while also reducing systemic immune stress responses.